I don't think the assigned USB bus number is related to the IRQ of the USB controller. But you can check this by comparing IRQs on the machines where the Bluetooth adapter worked, using IORegistryExplorer.
You can find the Bus Number under "LocationID" and "USBBusNumber" and the IRQ under "IOInterruptSpecifiers" at the root of each USB port.
In your BIOS there should be a "Plug & Play OS" setting somewhere. Set this to no. No is usually the default though.
Apart from that, the closest thing to what you're talking about that I know of are the OS-dependant code paths that exist in the DSDT table. But you say the DSDT is identical so yeah. Weird.
Maybe there's a way to inject your Bus Number via DSDT. I guess that injecting a "USBBusNumber" could probably work, in the same way that you can inject other device properties for LAN and Video cards. But I have never heard about anyone injecting such a value before. You should definitely experiment with this. Check this post at IM, it's not related to your issue but following the links in it should give you some inspiration regarding how to proceed.
http://www.insanelymac.com/forum/index.php?showtopic=225766&st=1060&p=1590490&#entry1590490Good Luck.